Microsoft PowerPoint - Module 3-2 Washer Extractors

8/12/2019 Microsoft PowerPoint - Module 3-2 Washer Extractors

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1

Sustainability

in commercial laundering processes

Module 3

Washing process

Chapter 2

Washing process in washer extractors

Leonardo da Vinci Project


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Module 3 Washing process Chapter 2 Washer extractors 2

Content

Domain of washer extractors

Kinds of processes

Design of process

Efficiency effects

Reduction of water consumption


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Learning targets

After finishing this chapter, you will

know the domain of washer extractors know and be able to differentiate different kinds of washing and

cleaning processes

know the requirements of wet-clean

be able to differentiate between wet-cleaning and dry-cleaning and

know when to apply which kind of process know, recognize and be able to name effects on wash program

design

know, recognize and be able to name efficiency effects


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Learning targets

know, recognize and be able to explain important factors to reducewater consumption

know the possibilities to modify washing and rinsing phases

know the function of water recovery systems

know and be able to explain the cascade principle


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Re-wash of laundry

Wash of heavily soiled laundry

Wash of textiles with

bleeding colours


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Small batches

Treatment of

high quality workwear


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Infectious laundry- Registered machine

according to RKI

Wash ofcleanroom laundry

Wash of medical devices


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Sensitive laundry: wool blankets, curtains

Special laundry items (e.g. mattresses)

Wet clean


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Kinds of cleaning process

Washing

- Laundering in water with established methods with common usage oftemperature, mechanical agitation and detergents

Dry cleaning

- Treatment in non-polar-solvents in special machines with adapted

programs and detergents

Wet cleaning

- Washing of sensitive outerwear with adapted programs (lowtemperature, low mechanical agitation and adapted detergents)

- Synonyms for wet-clean: Aquaclean, Aquatex, Permac etc.


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Effects on wash program design

Textiles

- Fibre substrate- Textile construction

- Colouration, print and special treatments

- Quality of making up

Soil

- Kind and amount


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Effects on wash program design

Water quality

Detergent/disinfection

Request on performance

- Spot free

- Hygienic clean


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Design of washing program

Program steps

Pre wash

Main wash

Rinse with intermediate spin

Neutralisation, Addition of Aids (starch, textile softener, acid)

Final spin


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Aims of pre washing

Rapid wetting of laundry

Swelling of soil

Removal of heavy soil from the laundry

Dissolving and swelling of spots


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Pre wash parameters

Durationapprox. 8 - 12 min

Temperature

depends on amount and kind of soilblood 20 25 C (> 30C denaturation/fixing of proteins)

fat/oil 50 60 C (> 50C good soil removal)

Detergents

50 70 % of total amount

reuse of rinse water increases detergent concentration

residues of peroxide cause denaturation/fixing of blood

Drain

in sewage


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Aims of main wash

Removal of remaining soil

Removal of oxidative spots

Disinfection (thermal) at temperature > 85 C

Disinfection (chemical) at 40 C

(depends on disinfectant)

Increase of textile whiteness


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Main wash parameters

Duration- approx. 10 15 min at temperature level

Temperature- adapted to washing process and amount and kind of soil

e.g. thermal disinfection10 min at 90 C or

15 min at 85 C

Drain

- in sewage


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Aims of rinse

Removal of soil residues

Removal of detergent residues(surfactants, alkali and bleaching agents)


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Rinse

Duration (total) approx. 8 12 min

Temperature approx. 60 25 C (without heating), depends on main

wash temperature

Drain in storage tanks

Inactivation of bleach agents is needed if extracted water is reused


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Neutralisation

In last rinse

Reduction of textile pH-value for the purpose of preventing yellowing

effect during drying or ironing process

Duration approx. 2 4 min

Temperature approx. 20 25C

Formic or acetic acid in last rinserecommended pH-values

flatwork 6,0-6,5fully dried laundry 6,0-6,5garments for tunnel finisher, flat press 5,5-6,5


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Spin

Mechanical dewatering by centrifugal forceg - factor up to 600

5 - 10 min

Water content of laundry depends ontype of fabrics, drum, number of revolution (rpm), duration, temperature oflaundry

Intermediate spinbetween rinsing bathsminimisation of carry over effects of detergent residues in next rinse bath

Problematic: wrinkling of PES/CO textiles at temperatures > 40C,

high rpm and/or spin duration


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Water saving possibilities: recovery system

Usage of storage tanks

- Use of water from last in first rinse

- Use of water from rinsing in pre- and main wash

- Last rinse with fresh water quality only

Savings

- Water up to 40 %

- Steam up to 45 %- Detergents up to 30 %

Environmentally friendly

Economical

- Quick return on investments


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Water saving possibilities: Cascade principle

Work wear- Hygienically non sensitive wear

only

-Average demands on quality

Wiping cloths, mops etc.- Hygienically non sensitive

Laundry only- Low demands on quality

Hotel linen- Hygienic sensitive laundry

- High demands on quality

-Low soiled

sewage


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Requirements for wet-clean

Low friction between textiles among each other and between textilesand drum

Low mechanical agitation of laundry- No intensive falling movement of laundry

- Decreased movement in washing liquor

Usage of adapted detergents to guarantee wash performance- Compensation of low mechanics by more efficient detergents, see

Sinner`s circle

- Protection of wool fibres against felting and shrinkage


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Requirements for wet-clean

Demands on machinery

Big drum volume (more than 120 L)

Possibility of free program design Rotation speed

Reversing

Washing liquor level

Exact control of temperature (30 35 C)


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Wet-cleaning effects vs. dry-cleaning effects

14Odour

2.52.5Shrinkage

23Greying

23Spots

15Sweat

2.52Soil

Wet cleaningDry-cleaning

1 = very good 5 = insufficient


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Textile care labelling wet clean

ISO/DIS 3758


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Wet-cleanable textiles

1. Coats, trousers, jackets2. Sport and water repellent textiles

3. Pullover (e. g. wool, angora, etc.)4. Silk and viscose textiles5. Cotton textiles with non solvent6. Compatible colourations or prints

7. Evening wear8. Blankets, curtains9. Quilts filled with wool, down or feathers10.Bathroom mats

Documents

Microsoft PowerPoint - Module 3-2 Washer Extractors